DatatypeInsideOntop

Datatype handling inside Ontop

Note that this page is only intended for ontop developers

Note that the behavior will be changed in the next stable release as described in OntopDatatypes

Datatypes inside ontop:

• SQL data type (DB and mappings) x #DBs,

• java.sql.jdbc.Types

• XSD data types (for Datalog) ans1(xsd:int(x))

• XML Schema

• COL_TYPE (used for the signature of the Predicate)

• CODE (for SQL generation)

• OWL Datatype (for OWLAPI)

• Sesame Datatype (for SESAME API)

• SQL CAST (for SQL Generation, in particular for aggregations)

Datatype conversions:

• OWL datatype -> COL_TYPE

OWLAPI3Translator
		private static Predicate.COL_TYPE getColumnType(OWLDatatype datatype) throws TranslationException 

• Sesame Datatype (XSD type) -> COL_TYPE

SesameRDFIterator
		private Predicate.COL_TYPE getColumnType(URI datatype) 

• COL_TYPE -> Sesame Datatype

SesameBindingSet
      private Binding createBinding(String bindingName) 

• XSD type -> CODE

	SQLGenerator
	private String getTypeColumnForSELECT(Term ht, List<String> signature, int hpos) 

• XSD type -> jdbc Type

	SQLGenerator
	private int getVariableDataType (Term term, QueryAliasIndex idx) 

• CODE -> COL_TYPE

QuestResultset
	private COL_TYPE getQuestType(int sqltype) 

• jdbc Type -> XSD type

TypeMapper
        private static TypeMapper typeMapper;

NOTE: we return the most general XSD datatype from the correspondent database SQL type.

• jdbc Type -> XSD type (use TypeMapper)

MappingDatatypeRepair 
     private Predicate getDataTypeFunctor(Map<String, List<Object[]>> termOccurenceIndex, Variable variable) throws OBDAException 

• jdbc Type -> DB specific type

SQLDialectAdapters
      public String sqlCast(String value, int type)  
      private static Map<Integer, String> SqlDatatypes

• XSD type -> COL_TYPE

SparqlAlgebraToDatalogTranslator
private COL_TYPE getDataType(LiteralImpl node) 

• COL_TYPE -> XSD type

SparqlAlgebraToDatalogTranslator
private Predicate getDataTypePredicate(COL_TYPE dataType) throws RuntimeException 

• XML Schema -> COL_TYPE

SparqlAlgebraToDatalogTranslator
private Function getConstantFunctionTerm(org.openrdf.query.algebra.ValueConstant expr) 

• COL_TYPE -> XSD type

ExpressionEvaluator
private Predicate getDatatypePredicate(Term term) 

##Using Datatypes

• COL_TYPE -> string

JDBCUtil 
        public String getSQLLexicalForm(ValueConstant constant)

• jdbc Type -> boolean true/false

SQLGenerator
	private boolean isStringColType